Methods and means for repairing cracked castings



F. SCHULTE June 10, 1958 METHODS AND MEANS FOR REPAIRING CRACKEDCASTINGS OriginalFiled April 10, 1950 FIG. 1.

INVENTOR.

FRANK SCHULTE ATTORNEY United States Patent METHODS AND MEANS FORREPAIRING CRACKED CASTINGS Continuation of application Serial No.155,053, filed April 10, 1950. This application December 24, 1956,

Serial No. 630,420

Claims. (Cl. 189--36) This invention relates in general to certainnew'and useful improvements in methods and means for repairing crackedcastings and, more particularly, to cracked cylinder blocks and cylinderheads for automotive engines. This application is a continuation of mycopending application Serial No. 155,053, filed April 10, 1950, nowabandoned.

At the present time it has become fairly widespread practice to repair,rebuild, and recondition automotive engines, and, in the process of sodoing, the engine is completely disassembled. The various componentparts are reconditioned or replaced and the engine is reassembled torestore itto a condition which is as nearly new as possible. In thecourse of these reconditioning operations one of the first steps is toinspect the cylinder block because most used cylinder blocks will befound to. have developed one or more cracks which would seriously impairthe future life of the entire reassembled engine if the crack wereallowed to remain. Experience has shown that a large percentage. of usedcylinder blocks are in this cracked condition and it would be impossibleto operate a plant for rebuilding and reconditioning automotive engines,without employing some method of repairing these cracked cylinder.blocks. A number of such methods have been proposed but, for the mostpart, cracks which have heretofore been repaired tend toreappear insubsequentuse thereby shortening the life of the reconditioned engine.Furthermore, methods which are presently in use are complicated andexpensive in terms of materials and labor.

It is, therefore,one of the primary objects of the present invention toprovide a method and means for repairing cracked castings,such as,automotive cylinder blocks and thelike, which is simple and economicalin terms of time and materials, and results in a complete and durablerepaired area, which will not later tend to open up or become furtherdamaged due to expansion and contraction and other normal operatingcharacteristics of the automobile engine.

it is a further object of the present invention to provide a simple andcompletely satisfactory method for repairing automotive cylinder blocksand similar types of castings, which method will result in a repair thatdoes not tend to open up later under vibration and shock normallyencountered in automobile operation.

With the above and other objects in view, my invention resides in thenovel features of form, construction, arrangement, and combination ofparts presently described and pointed outin the claims.

in the accompanying drawing- Fig. l is a fragmentary elevational viewofa section of an automobile cylinder block, which has been drilled as afirst step in the method of the present invention;

Fig. 2 is a longitudinal sectional view of line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view taken along line 3-3 of'Fig. 2;

Patented June 10, 1958 'ice Fig. 4 is a perspective view of the repairinsert forming a part of the present invention; and

Fig. 5 is a perspective view of the insertable plug element also forminga part of the present invention.

Referring now in more detail and by reference characters to the drawing,which illustrates a preferred embodiment of the present invention, Adesignates a section of an automobile cylinder block in which a longhair-like crack 0 has been located by any available method of inspectionand crack location.

In applying the repair method of the present invention, the first stepis to drill two holes 1 at the opposite ends of the crack 0, in such amanner that the center points of the holes 1 are approximately alignedwith the terminal ends of the crack 0, and the outer areas of thedrilled holes I extend into clean uncracked metal. Next a series ofuniformly spaced additional holes 2 of substantially the same size asholes 1 are drilled along the crack. For convenience it has been foundthat these holes should be located at approximately an inch to an inchand a constitute a critical factor.

The holes 1 and 2 are then tapped with a tapering thread. Next a seriesof shallow recesses 3 are formed in the face of the cylinder block, eachrecess 3 being located approximately midway between successive holes 2,or at the ends between holes 1, 2., and straddling the crack 0. Therecesses 3 are formed by drilling two annular recesses with a tubularcutter in an intersecting pattern to form a figure 8, the central orcrossover portion of which is located on the crack 0, as best seen inFig. 1.

Provided for snug-fitting insertion within the recesses 3 are insertelements 4 also having the intersecting pattern forming a figure 8, andpreferably being slightly larger in dimensions than the recesses 3 so asto fit therein tightly when driven home with a hammer, once such insertelement being thus placed in each recess 3. It will be noted that theinner apertures 5 of the element 4 encircle the upstanding circularbutton-like portions of metal m left within the interior of the recesses3, so as to hold the metal of the casting A together across the crack 0against any extensive or disruptive forces. Preferably the elements 4are slightly thicker than the depth of the recesses 3 for purposespresently more fully appearing.

Also provided for use in the present invention is an insertable member,which comprises a short section of circular steel rod 6 bent over inL-shaped fashion at its one end to provide a handle 7. At its other endthe rod 6 is threaded with a coarse tapering thread as at 8, andinwardly of such thread, is cut partially through, as at 9, by means ofa hack saw, file, or any other similar cutting tool. inserted into oneof the holes 1 and screwed down tightly in place. Inasmuch as the threadis a very coarse thread and since the rod is preferably made ofcomparatively ductile material the threaded portion will become tightlyjammed in the hole 1, and upon continued turning will twist off in theregion of the cut or notch 9 leaving the threaded end in place in thehole 1, in the formation of a wedging plug 10. Similarly, plugs aredriven into the other holes 1 and 2, as shown in Fig. 2. It should benoted, in this connection, that the coarse tapered thread has the effectof jamming the holes 1 and 2 so as to tend to stretch the metal in theregion of the crack 0. This action places the elements 4 under tensionand the crack 0 is, in effect, forced apart by the plugs 10, but at thesame time is held together by the elements 4. The forces, in effect,work against each other. 7

Finally, the exposed faces of the plugs 10, the exposed areasof thecrack c, and the exposed faces of the elements 4 are thoroughly peenedwith a suitable peening tool so that the metal of the casting, the metalof the The other end of the rod 6 is then J plugs 10, and the metal ofthe elements 4 are bonded thoroughly together, and the crack iscompletely closed. The area may then be bufied or ground off andsmoothed down as a final finishing operation.

It will be apparent that when the insert 4 is positioned within therecesses 3, the central waisted portion, which joins the two fiatcircular annuli forming the insert 4, will extend approximately alongthe line of the crack c. By reason of the fact that the insert 4 isformed of two intersecting circular annuli, when the cylinder block A issubjected to elevated temperatures and expands, the insert t will alsoexpand and set up forces acting radially of the annuli and in thedirection of the crack 0. These forces set up components of forcecrosswise of the crack 0 and also along the length of the crack 0thereby urgingthe edges of the crack c together. The expansion of the:insert 4 also produces a tendency for the inner edges of the annuli tomove inwardly, but since the annuli. are placed within the conformingrecesses 3, the button-like portions m, m, of the cylinder block A willalso expand so that the forces which urge the inner edges of the annuliinwardly will be counteracted by the forces due to the expansion of. thebutton-like portions m, m.

It should be understood that changes and modifications in thearrangement and combination of the several steps of the methods forrepairing cracked castings and in the form of construction orarrangement of the means forming a part of and used in said method, maybe made and substituted for those herein described without departingfrom the nature and principle of'my invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. The method of repairing cracked castings such as automotive cylinderblocks and the like which comprises drilling a series of spaced holesalong the crack, forming a plurality of shallow annular recesses, theouter peripheral surfaces of which overlap chordwise so that the crackextends approximately along the chord common to said outer peripheralsurfaces, inserting tension-resisting members in each recess so as tooppose forces tending to widen the crack, said tension resisting membersbeing of substantially similar geometrical shape to the recesses,forcing into each of the holes a wedging member tending to spread thecrack, and peening the crack and inserted elementsto seal them together.

2. The method of repairing cracked castings such as automotive cylinderblocks and the like which comprises drilling a series of spaced holesalong the crack, one of said holes being located around each end of thecrack,

forming a plurality of shallow annular recesses, the outer peripheralsurfacesvof which overlap chordwise so that the crack extendsapproximately along the chord common to said outer peripheral surfaces,inserting tensionresisting members in each recess so as to oppose forcestending to widen the crack, said tension-resisting members being ofsubstantially similar geometrical shape to the recesses, forcing intoeach of the holes a wedging member tending to spread the crack, andpeening the crack and inserted elements to seal them together.

3. The method of repairing cracked castings such as automotive cylinderblocks and the like which comprises drilling a series of spaced holesalong the crack, one of said holes being located around each end of thecrack so that such hole completely encircles the end of the crack,forming a plurality of shallow annular recesses, the outer peripheralsurfaces of which overlap chordwise so that the crack extendsapproximately along the chord common to said outer peripheral surfaces,inserting tension-resisting members in each recess so as to opposeforces tending to widen the crack, said tension-resisting members beingof substantially similar geometrical shape tothe'recesses, forcing intoeach of the holes a wedging member tending to spread the crack, andpeening the crack and inserted elements to seal them together.

4. A repaired cracked casting having a recess consisting of two arcuateannuli overlapping chordwise, and an insert element having the contourof two intersecting arcuate annuli integrally joined together along ashort portion of their peripheries in the provision of a central waistedarea the line of juncture between said annuli being a chord common tothe outer peripheral circles of both annuli, said insert beingsubstantially similar in geometric shape to the recess of the castingand being inserted therein tightly and self-retentively so that saidline of juncture extends approximately along the crack.

5. A repaired cracked casting having a recess consisting of two arcuateannuli of uniform and equal width overlapping chordwise, and an insertelement having the contour of two flat circular intersecting annuliintegrally joined together along a short portion of their peripheries inthe provision of a central waisted area, the line of juncture betweensaid annuli being a chord common to the outer peripheral circles of bothannuli, said insert being substantially similar in geometric shape tothe recess of the-casting and being inserted'therein tightly andself-retentively so that the waisted area will extend approximatelyalong the crack.

6. A repaired cracked casting having a recess consisting of two circularannuli overlapping chordwise, and an insert element having the contourof two intersecting circular annuli integrally joined together along ashort portion of their peripheries in the provision of a central waistedarea, the line ofjuncture between said annuli being a chord commonltothe outer peripheral circles of both annuli, saidi insertv beingsubstantially similar in geometric shape" to the recess of the casting.and being inserted therein tightly" and. self-'retentively so that saidline of juncture" extends approximately along the crack.

7. A repaired cracked castinghaving a recess consisting of two arcuate'annuli arranged: in intersecting relation and. extending sothat thelongitudinal axis' between the lobes of the recess will lie crosswise ofthe crack, and an insert element having the contour of two intersectingarcuate annuli integrally joined together along a short portion of theirperipheries in the provision of a central waisted area, the line ofjuncture between said annuli being a chord common to the outerperipheral circles of both annuli, said insert being substantiallysimilar in geometric shape to the recess of thecasting and beinginserted therein tightly and self-retentively, said insert being sopositioned with reference to the crack that said waisted area willextend approximately along the-crack.

8. A repaired cracked casting having a recess consisting of two arcuateannuli arranged in intersecting relation and extending so that thelongitudinal axis between the lobes of the recess will lie crosswise ofthe crack, and an insert element having the contour of two intersectingarcuate annuli integrally joined together along a short portion of theirperipheries in the provision of a central waisted area, the line ofjuncture between said annuli being a chord common to the outerperipheral circles of both annuli, said insert being substantiallysimilar in geometric shape to the recess of'the casting and beinginserted therein tightly and self-retentively so that said line ofjuncture extends approximately along the crack.

9. A repaired cracked casting having a figure-8 shaped recess formedtherein, said recess having the geometrical shape of two fiat circularannuli of uniform and equal width arranged in intersecting rclation'andextending so that the longitudinal axis between the lobes of the recess= will lie crosswise of the crack, and an insert element formed ofsheet steel and. consisting of two flat circular annuli of uniform andequal radial width arranged in intersecting relation and integrallyjoined together along a short portion of their periphery in theprovision of a central waisted area, the line of juncture between saidsesame annuli being a chord common to the outer peripheral circles ofboth of the annuli so that all portions of the periphery of the insertelement conform to circular arcs, said elements being tightly andself-retentively peened into said recess, whereby to hold the cracktogether against crack-opening forces when the casting tends to expandunder conditions of elevated temperature.

10. A repaired cracked casting having a figure-8 shaped recess formedtherein, said recess having the geometrical shape of two flat circularannuli of uniform and equal radial width arranged in intersectingrelation and extending so that the longitudinal axis between the lobesof the recess will lie crosswise of the crack, and an insert elementformed of malleable sheet steel capable of being deformed upon peening,and consisting of two flat circular annuli of uniform and equal radialWidth arranged in intersecting relation and being integrally joinedtogether along a short portion of their peripheries, the line ofjuncture between said annuli being a chord common to the outerperipheral circles of both annuli, said insert having the sameperipheral shape and contour as the recess of the casting being repairedand being substantially thicker than such recess so as to be adapted forsnug-fitting insertion within the recess and being peened down andthereby adapted for tightly hammered fit within the recess, said recessand insert being so positioned with reference to the crack that thenarrow central portion of the recess and insert will extendapproximately along the crack.

References Cited in the file of this patent UNITED STATES PATENTS KirbyJuly 28, 1942

